It is common to etch through various oxides during semiconductor processing. Exemplary oxides include silicon dioxide, and doped silicon dioxide (such as, for example, borophosphosilicate glass (BPSG), and phosphosilicate glass (PSG)). Oxides are common in semiconductor processing due to their electrically insulative properties, and due to their ease of formation (for instance, oxides can be formed as spin-on-dielectric materials, or by numerous deposition methods, including, for example, chemical vapor deposition (CVD) methods).
It is common for oxides to be formed over electrically conductive nodes, and for openings to subsequently be etched through the oxides to the electrically conductive nodes to expose the nodes for subsequent processing. The openings are formed with etch chemistry which removes the oxide. In some aspects, the openings can be formed with multiple etch chemistries. For instance, a first etch chemistry can be utilized to create the openings, and a second etch chemistry can be utilized to clean debris that may have been formed by the first etch chemistry.
Problems can occur during formation of openings extending into oxides, in that one or more of the etch chemistries utilized during the formation of the openings can undesirably roughen the exposed oxide surfaces. For instance, substantially planar oxide surfaces may be exposed to the etch chemistry utilized to etch oxide-containing debris from within openings, and such surfaces may be undesirably roughened by such etch chemistry. Accordingly, it is desired to develop new methods for etching oxides.